<!DOCTYPE html>
<html lang="en">
    <head>
    	<title>DOM操作</title>
        <meta charset="utf-8">
       
    </head>
    <body>
    	<script type="text/javascript">
    		var html = document.documentElement;
    		console.log( "html === document.childNodes[0] ：" + (html == document.childNodes[0]));
    		console.log("html === document.firstChild:" + (html == document.firstChild));
    		var body = document.getElementsByTagName('body');
    		console.log("body === document.body:" + (body == document.body));
    	</script>
    </body>
</html>